Author Topic: TPMS inaccurate in the cold?  (Read 5793 times)

Offline Mister Tee

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TPMS inaccurate in the cold?
« on: December 18, 2011, 01:13:22 pm »
Ok so get up at zero dark thirty and it's hella cold out there, and in the garage.  I just returned from six weeks in Southeast Asia so my bike has sat all that time.  Everything looks fine, tires appear hard, and I'm out for a short ride.  Fire up the bike (whew, it still cranks) and take off.  TPMS shows 38 F 41 R.  A tad lower than I want, but fine for now.

The bike just doesn't feel right.  Steering is heavy, it just feels off.  Granted, I've been tooling around on a 125 cc Honda Elite motorbike for the last six weeks, so I chalk it up to that.  Later in the day, when it's warmer and I feel like screwing around in the garage, I fire up the compressor so I can fill all tires that need filling.  My slime gauge reads 32 F 38 R (WTF?)  so I fill it back up to 42/42, which is where I like it.  Get back on the bike.  Rides like it should, feels good again.  TPMS is reading 47/47.

TPMS so far has been fairly accurate, to within a couple pounds of a gauge, but for whatever reason it's really off now.  The only thing that is different between now and six weeks ago is that it was a whole lot warmer outside.  Anyone else notice that?

Offline McJunkie

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Re: TPMS inaccurate in the cold?
« Reply #1 on: December 18, 2011, 02:51:13 pm »
Same thing happened to me. Once it got cold out the TPMS read 3-5 lbs higher than the Accu-Gauge I use. Took the gauge inside for a day to warm it up and now it's back to being only 1 lb off. I attribute it to the gauge being affected by the temp rather than the TPMS. Maybe it's a little of both.

Offline PH14

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Re: TPMS inaccurate in the cold?
« Reply #2 on: December 18, 2011, 05:09:25 pm »
I juste went out, it's about 32F out and my TPS is spot on. I have always had no issue with it, it reads the same as the gauge I use no matter the temp.

Offline jjsC6

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Re: TPMS inaccurate in the cold?
« Reply #3 on: December 18, 2011, 05:19:57 pm »
I suggest a forum search.  The system compensates for temperature.  Don't ask me to explain it - it's magic.  I'll try to find it.

Here... http://www.zggtr.org/index.php?topic=1248.msg12456#msg12456

BTW, the chart does not jive with what you are seeing, but it's good information anyway.
Jim
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Current bikes....
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Offline Mister Tee

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Re: TPMS inaccurate in the cold?
« Reply #4 on: December 18, 2011, 05:32:29 pm »
I suggest a forum search.  The system compensates for temperature.  Don't ask me to explain it - it's magic.  I'll try to find it.

Here... http://www.zggtr.org/index.php?topic=1248.msg12456#msg12456

BTW, the chart does not jive with what you are seeing, but it's good information anyway.


Yes, I know about forum searches!  I am familiar with the temperature compensation feature of TPMS.  I am observing what I believe to be an, I need a word.  Anomoly.  I have observed an anomoly.  That is the justification I am using to start a new topic.

Offline jjsC6

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Re: TPMS inaccurate in the cold?
« Reply #5 on: December 18, 2011, 07:08:50 pm »
Yes, I know about forum searches!  I am familiar with the temperature compensation feature of TPMS.  I am observing what I believe to be an, I need a word.  Anomoly.  I have observed an anomoly.  That is the justification I am using to start a new topic.

Wow, didn't mean to offend you with my reply  ;)
Jim
2010 Concours - Sold Feb 2013
Current bikes....
2011 Ninja 1000, 2013 BMW 1600 GT, 2012 Ducati Panigale

Offline Mister Tee

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Re: TPMS inaccurate in the cold?
« Reply #6 on: December 19, 2011, 11:12:05 am »
Sorry - I mod on another site and call people out all day long for not doing forum searches.  I was half cranky and half joking!

Offline Rhino

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Re: TPMS inaccurate in the cold?
« Reply #7 on: December 19, 2011, 11:38:26 am »
The accuracy of my TPMS has changed over time. It changed a lot with my last rear tire change. it now reads 3-4 psi low. Whenever I check my tires I always match it to the TPMS so I have an idea of what the actual pressure is.

Offline Tim

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Re: TPMS inaccurate in the cold?
« Reply #8 on: December 19, 2011, 01:53:52 pm »
I bet it was some what warmer 6 weeks ago. 6 weeks ago I would still be riding.   ;)

As the temps go down so does the air pressure in your tires. (cars too) I like to have the proper T/P when I take off but normally once the tires warm up a bit, the sensors get closer to being what I want. I've seen the T/Ps go up and down just by going from warmer outside air to colder outside air or visa versa while out on a ride. 

Could be the battery in your fob is getting weak.
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Offline jjsC6

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Re: TPMS inaccurate in the cold?
« Reply #9 on: December 19, 2011, 02:37:11 pm »
Sorry - I mod on another site and call people out all day long for not doing forum searches.  I was half cranky and half joking!

I wasn't cranky, but I was only half joking as well (hence the  ;)). 
Jim
2010 Concours - Sold Feb 2013
Current bikes....
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Offline VirginiaJim

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Re: TPMS inaccurate in the cold?
« Reply #10 on: December 19, 2011, 03:12:31 pm »
Mine seem more 'off' with the cold as well...  I don't worry about it.  I check with the gage before starting out.  I only use the TPMS for wild swings down.  I wouldn't trust it for anything else.
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Offline rcannon409

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Re: TPMS inaccurate in the cold?
« Reply #11 on: December 19, 2011, 05:12:33 pm »
Mine read low in warm (85 degree plus) temps.  In the 30-50 range its accurate.  I have a decent Factory KTM gauge and the TPS is always 3-4 psi lower than it is. I did notice at 12 degrees my front tps gave me a low battery warning.


Offline PH14

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Re: TPMS inaccurate in the cold?
« Reply #12 on: December 19, 2011, 06:19:39 pm »
I only use the TPMS for wild swings down. 

+1

Offline Curt

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Re: TPMS inaccurate in the cold?
« Reply #13 on: December 20, 2011, 09:05:38 am »
the TPMS on my '08 has been inaccurate from day one. however, it is consistantly inaccurate. TPMS actually reads 4 pounds higher than any of my gauges. It is not a feature that I will spend any money to fix when the warranty expires.

Offline B.D.F.

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Re: TPMS inaccurate in the cold?
« Reply #14 on: December 20, 2011, 12:47:44 pm »
The tire pressure sensors are temperature compensated and will not read the same as a normal (not temperature compensated) tire pressure gauge. If the tires were pressurized to 42 PSI at 70 degrees F for example, when the temp. drops to 40 F the pressure will drop to something like 39 PSI, which an external gauge will show. The TPS sensors will continue to show the pressure is something like 42 PSI at the lower temp. So if you inflate the tires to the higher pressure at a lower temperature, the TPS will show a higher reading because of the low temperature.

The reason the sensors are temperature compensating is so that the pressures do not read very high when riding the bike- it would tend to put the owner off and would probably lead to him / her stopping and reducing the tire's pressure while hot (which is not the right thing to do). Compensating for temperature is a judgment call that the chip manufacturer made when designing the controller.

Brian



Ok so get up at zero dark thirty and it's hella cold out there, and in the garage.  I just returned from six weeks in Southeast Asia so my bike has sat all that time.  Everything looks fine, tires appear hard, and I'm out for a short ride.  Fire up the bike (whew, it still cranks) and take off.  TPMS shows 38 F 41 R.  A tad lower than I want, but fine for now.

The bike just doesn't feel right.  Steering is heavy, it just feels off.  Granted, I've been tooling around on a 125 cc Honda Elite motorbike for the last six weeks, so I chalk it up to that.  Later in the day, when it's warmer and I feel like screwing around in the garage, I fire up the compressor so I can fill all tires that need filling.  My slime gauge reads 32 F 38 R (WTF?)  so I fill it back up to 42/42, which is where I like it.  Get back on the bike.  Rides like it should, feels good again.  TPMS is reading 47/47.

TPMS so far has been fairly accurate, to within a couple pounds of a gauge, but for whatever reason it's really off now.  The only thing that is different between now and six weeks ago is that it was a whole lot warmer outside.  Anyone else notice that?
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